12200-23-6Relevant academic research and scientific papers
Structure and bonding of the hexameric platinum(II) dichloride, Pt6Cl12 (β-PtCl2)
Von Schnering, Hans Georg,Chang, Jen-Hui,Peters, Karl,Peters, Eva-Maria,Wagner, Frank R.,Grin, Yuri,Thiele, Gerhard
, p. 516 - 522 (2003)
The crystal structure of Pt6Cl12 (β-PtCl2) was redetermined (R3m ah = 13.126 A, ch = 8.666 A, Z = 3; arh = 8.110 A, α = 108.04°; 367 hkl, R = 0.032). As has been shown earlier, the structure is in principle a hierarchical variant of the cubic structure type of tungsten (bcc), which atoms are replaced by the hexameric Pt6Cl12 molecules. Due to the 60° rotation of the cuboctahedral clusters about one of the trigonal axes, the symmetry is reduced from Im3m to R3m (I3m). The molecule Pt6Cl12 shows the (trigonally elongated) structure of the classic M6X12 cluster compounds with (distorted) square-planar PtCl4 fragments, however without metal-metal bonds. The Pt atoms are shifted outside the Cl12 cuboctahedron by Δ = +0.046 A (d(Pt-Cl) = 2.315 A; d(Pt-Pt) = 3.339 A). The scalar relativistic DFT calculations results in the full m3m symmetry for the optimized structure of the isolated molecule with d(Pt-Cl) = 2.381 A, d(Pt-Pt) = 3.468 A and Δ = +0.072 A. The electron distribution of the Pt-Pt antibonding HOMO exhibits an outwards-directed asymmetry perpendicular to the PtCl4 fragments, that plays the decisive role for the cluster packing in the crystal. A comparative study of the Electron Localization Function with the hypothetical trans-(Nb2Zr4)Cl12 molecule shows the distinct differences between Pt6Cl12 and clusters with metal-metal bonding. Due to the characteristic electronic structure, the crystal structure of Pt6Cl12 in space group R3m is an optimal one, which results from comparison with rhombohedral Zr6I12 and a cubic bcc arrangement.
